Workflow designer crash with adding removed worker

1) Create "Element with command line tool" with name "test" and any slots.

2) Use context menu on "test" element in "Custom Elements with CMD Tools" in "Elements", click "Remove"
3) Use context menu on WD main window, add element -> "Custom Elements with CMD Tools". Select "test", UGENE crashes.

Expected state: There shouldn't be "test" element on the step 3 after removing it